* TSX down 284.73 points, or 2.31 percent, at 12,051.30
* All 10 of the TSX's main groups fall
* 13 declining stocks for every gainer
TORONTO, Jan 15 (Reuters) - Canada's main stock index fell more than 2 percent in morning trading on Friday, pressured by a sustained slide in crude oil prices that weighed on energy shares as well as banks, industrial and consumer names.
The index is heading for a more than 3 percent drop for the week, as the low oil prices hurt Canada's substantial energy sector and economic worries more broadly gave investors reason to retreat.
Crude is near 12-year lows as the market braces for increased Iranian oil exports once international sanctions are lifted, possibly within days.
At 10:20 a.m. EST (1520 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 284.73 points, or 2.31 percent, at 12,051.30.
It has fallen more than 9 percent since returning from the Christmas break.
The most influential movers on the day were banks and energy stocks. The country's largest lender, Royal Bank of Canada , fell 2.7 percent to C$67.70, and one of its biggest drillers, Canadian Natural Resources lost 6.5 percent to C$24.21.
But the losses were broad: every sector was in the red, and most were off at least 1.5 percent.
The energy group retreated 4.7 percent, and financials lost 2.3 percent.
TransAlta Corp declined 9.2 percent to C$3.96 after the power generation company slashed its dividend to fund its transition away from coal.
The utilities group to which TransAlta belongs fell 1.8 percent.
Industrials lost 2.1 percent, with Canadian National Railway down 2.2 percent at C$72.52.
The materials group, which includes precious and base metal miners and fertilizer companies, lost 0.5 percent.
It was helped by gains for gold miners, as bullion climbed nearly 2 percent.
Barrick Gold Corp rose 5.2 percent to C$11.47, and Detour Gold Corp jumped 10.7 percent to C$16.97 after announcing results late on Thursday.
Declining issues outnumbered advancers by 13 to 1, with 46 stocks setting 52-week lows. (Reporting by Alastair Sharp; Editing by Lisa Von Ahn)